Fix constant folding through bitcasts by no longer relying on undefined behaviour (converting NaN values between float and double).

SelectionDAG::getConstantFP(double Val, EVT VT, bool isTarget);
should not be used when Val is not a simple constant (as the comment in
SelectionDAG.h indicates). This patch avoids using this function
when folding an unknown constant through a bitcast, where it cannot be
guaranteed that Val will be a simple constant.

llvm-svn: 163703

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index d85d41bd86a..b515fbaf600 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2454,9 +2454,9 @@ SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL,
     }
     case ISD::BITCAST:
       if (VT == MVT::f32 && C->getValueType(0) == MVT::i32)
-        return getConstantFP(Val.bitsToFloat(), VT);
+        return getConstantFP(APFloat(Val), VT);
       else if (VT == MVT::f64 && C->getValueType(0) == MVT::i64)
-        return getConstantFP(Val.bitsToDouble(), VT);
+        return getConstantFP(APFloat(Val), VT);
       break;
     case ISD::BSWAP:
       return getConstant(Val.byteSwap(), VT);